Assessment of local genetic structure and connectivity of the common eelgrass Zostera marina for seagrass restoration in northern Europe

L Martínez-García,B Hansson,J Hollander

doi:10.3354/meps13658

L Martínez-García, B Hansson + Show 1 more

https://doi.org/10.3354/meps13658

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Abstract

Seagrass meadows are one of the most important habitats in coastal regions since they constitute a multifunctional ecosystem providing high productivity and biodiversity. They play a key role in carbon sequestration capacity, mitigation against coastal erosion and as nursery grounds for many marine fish and invertebrates. However, despite these ecosystem functions and services, seagrass meadows are a threatened ecosystem worldwide. In the Baltic Sea, seagrass meadows have declined rapidly, mainly because of eutrophication, anthropogenic activities and climate change. This decline has the potential to erode the genetic variation and genetic structure of the species. In this study, we assessed how genetic variation and genetic differentiation vary amongZostera marinameadows and with a number of environmental characteristics in the county of Scania in southern Sweden. A total of 205 individuals sampled at 12 locations were analysed with 10 polymorphic microsatellite loci. Results showed that in spite of anthropogenic impacts and climate change pressures, locations ofZ. marinapossessed high genetic variation and weak genetic differentiation, with 3 major genetic clusters. Long-distance dispersal and/or stepping-stone dispersal was found among locations, with higher migration rates within the west coast. Organic matter, salinity and maximum depth appeared to be factors most strongly associated with the genetic structure and morphological variation ofZ. marina. These findings contribute significantly in the identification of potential donor sites and the viability of impacted areas to recover from natural recruitment, for the development of effective transplantation measures ofZ. marinain the southern Baltic Sea and temperate regions elsewhere.

Highlights

Global climate change and increasing rates of coastal urbanization and fisheries are promoting the loss of our coastal ecosystems (Waycott et al 2009, Boström et al 2014)
Optimal restoration of seagrass meadows is dependent on habitat quality and environmental characteristics as well as the genetic potential of the seagrass populations, as this factor has a conclusive influence on conservation success (Ferber et al 2008)
There were 7 to 24 unique multilocus genotypes (MLGs) identified per location (Table 2), resulting in 195 genotypically unique individuals that were used for further analysis

Summary

Introduction

Global climate change and increasing rates of coastal urbanization and fisheries are promoting the loss of our coastal ecosystems (Waycott et al 2009, Boström et al 2014). As a result of these losses, adverse damages at shorelines — caused by elevated sea levels, intense rainfall and extreme weather events — combined with the slow rate of recovery of seagrasses meadows requires human intervention through different actions such as restoration (Jackson et al 2021). Optimal restoration of seagrass meadows is dependent on habitat quality and environmental characteristics as well as the genetic potential of the seagrass populations, as this factor has a conclusive influence on conservation success (Ferber et al 2008). An understanding of the connectivity of populations can provide significant information about the species’ biology and evolutionary dynamics in terms of gene flow, recolonization, adaptation and, species resilience Genetic diversity, clonal diversity (R), genetic structure and connectivity within and between populations are all important for species persistence (Ferber et al 2008, Connolly et al 2018)

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